using System.Collections.Generic;
using System.Linq;
using System;

public class P
{
    public int x { get; set; }
    public int y { get; set; }
}

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var h = int.Parse(line[0]);
        var w = int.Parse(line[1]);
        line = Console.ReadLine().Trim().Split(' ');
        var sx = int.Parse(line[0]) - 1;
        var sy = int.Parse(line[1]) - 1;
        var gx = int.Parse(line[2]) -1;
        var gy = int.Parse(line[3]) -1;
        var map = new int[h, w];
        for (int i = 0; i < h; i++)
        {
            var s = Console.ReadLine().Trim();
            for (int j = 0; j < w; j++)
                map[i, j] = int.Parse(s[j].ToString());
        }
        var res = goDfs(map, sx, sy, gx, gy);
        Console.WriteLine(res ? "YES":"NO");
    }
    public static bool goDfs (int[,] map , int sx, int sy, int gx, int gy)
    {
        var h = map.GetLength(0);
        var w = map.GetLength(1);
        var dx = new int[] { 0, 1, 0, -1 };
        var dy = new int[] { 1, 0, -1, 0 };
        var used = new bool[h, w];
        var q = new Queue<P>();
        q.Enqueue(new P { x = sx, y = sy });
        used[sx, sy] = true;
        while (q.Count() > 0)
        {
            var a = q.Dequeue();
            if (a.x == gx && a.y == gy) return true;
            used[a.x, a.y] = true;
            for (int i = 0; i < 4; i++)
            {
                var nx = a.x + dx[i];
                var ny = a.y + dy[i];
                var nx2 = a.x + 2 * dx[i];
                var ny2 = a.y + 2 * dy[i];
                var nxm = (a.x + nx2) / 2;
                var nym = (a.y + ny2) / 2;
                if (nx >= 0 && nx < h && ny >= 0 && ny < w && Math.Abs(map[nx, ny] - map[a.x, a.y] )<= 1 && !used[nx, ny]) q.Enqueue(new P { x = nx, y = ny });
                if (nx2 >= 0 && nx2 < h && ny2 >= 0 && ny2 < w && map[nxm,nym]< map[a.x,a.y] && map[nxm,nym] < map[nx2,ny2] && !used[nx2,ny2] ) q.Enqueue(new P { x = nx2, y = ny2});
            }
        }
        return false;
    }
}